The present invention relates to a thread receiving tube for mounting on a spindle in a thread spinning machine.
In the textile industry and in particular with thread spinning machines, new receiving tubes are used several times every day with each twisting/spinning mechanism on the machine. With conventional tubes, the only centering capability inheres in the lower end of the tube which is typically gripped against a cone of the spindle. More typically, spring loaded calotte shaped cams are provided on the spindle circumference at about 5/6 of the spindle height. Such cams may not adequately center the tube, as the springs can have variable manufacturing deviations. This type of gripping may sometimes be satisfactory at normal spindle rotational speeds of up to 22,000 rpm. The trend, however, is towards increased rotational speeds where further problems can arise. Calotte shaped cams have been flung out of an empty spindle by centrifugal force. On the one hand, this presents a danger to operating personnel and at the very least, the spindles may become imbalanced. In addition, repairs to the affected spindles may have to be effected, which under certain circumstances involves a complete shut down of an entire ring spinning machine. Further disadvantages are that the spring loading of calotte springs may be reduced due to the increased centrifugal force, such that the tubes may shake and may not be held correctly on a spindle also causing imbalance problems. Further as a result of the inherent elasticity of a typical tube material, the tube diameter portion which engages around a spindle cone widens, such that the gripping effect relaxes.
It is therefore an object of the present invention to provide a thread tube for use at high speeds which overcomes the previously mentioned disadvantages and which is engaged more firmly on a spindle at increasingly high rotational speeds, whereby more exact coaxial alignment may be maintained.